Structures formed from interconnected lengths of tubing are known. For example, tubing may be variously connected to provide a temporary modular structure for supporting a sign or a banner.  It is advantageous if the lengths of tubing are easily interconnected and provide a structure that is rigid and adapted to be readily disassembled for later reuse.
A frequent problem is that repeated assembly and disassembly of the tubing causes wear to the structural components. In particular, a connector inserted within and then removed from the ends of the tubes causes wear to the interior of the tube. Eventually, the wear to the interior of the tube becomes so great that the connector cannot compensate for variances in wall thickness and a rigid connection with the tube is no longer possible. Variances in tube thickness may also result during manufacture and similarly contribute to a connection problem. Even small differences in the thickness of tube to be connected can result in a poor connection and insufficient rigidity of the interconnected structure.
Expandable connectors adapted to be inserted within the interior of adjacent tubes are known however these devices are not satisfactory. In particular, these devices do not provide a high degree of surface contact between the connector and the interior of the tube to be connected and only provide contact at discrete locations. As is apparent, such connections do not result in a sturdy and rigid connection along the entire surface area of the connector. Second, the prior art connectors are designed to bite into the interior wall of the tube thereby resulting in excessive wear to both the connector and the tube wall. Third, expandable prior art connectors do not apply contact pressure against the tube in a uniform manner. This  results in a less than rigid connection and causes uneven wear to the connected tube.
In view of the above, the present invention provides a connector for tubing adapted to compensate for wear or variances in thickness of the tubing wall and to provide a circumferentially uniform contact force against the tube being connected as well as to provide a large surface area of contact between the connector and the tube. In addition, the connector of the present invention has an uncomplicated design providing a reliable connector that is easily disassembled for servicing or repair.
In summary, the present invention is directed to a connector for tubing comprising a central body having a longitudinal axis extending from a first end to a second end, the central body comprising first and second cooperating members, an expansion mechanism for selectively moving the first and second cooperating members in a direction transverse to the longitudinal axis of the central body and at least first and second wedge members surrounding the central body in an equidistant manner and resting against the central body from about the first end to the second end so that when the first and second cooperating members are moved apart by the expansion mechanism, the wedge members are urged in a direction outwardly from the central body along the longitudinal axis thereof to engage against the interior of a tube to be connected. 